Constructing cable networks for the purpose of signal transmission, for instance glass fiber networks, typically involves combining optical glass fibers from different parts of the network. This is relatively difficult, since glass fibers can break during such an operation. In addition, typically, a minimum distance of about 20 meters is used between two nodes in a glass fiber network due to optical requirements (in particular regarding noise), so that a conductor repair length needs to have this minimum length.
Welding optical fibers is a critical process which requires a clean environment. Usually, coupling is done aboveground (for instance outside a channel or trench in which the cable has been laid). It is known to install extra cable length to this end. A drawback is that it is then necessary that this extra cable length is installed at the right location, at least there where, for instance, a branch needs to be made.
From the prior art, for instance, a cable is known which is provided with a so-called SZ-stranded cable, where the wire winding direction is periodically inverted to create extra glass fiber length, see for instance U.S. Pat. No. 6,795,625 B1, with the purpose to be able to compensate for thermal and mechanical length variations of the cable. In this case, the extra glass fiber length can only be used to be able to reach glass fibers easily to take them out (without disturbing or even cutting other glass fibers) and the required length of glass fiber is obtained by opening a relatively long part of the cable.
JP63201611 describes a flat body with a narrow slot in which an optical fiber is received.
U.S. Pat. No. 4,146,302 describes a communication cable, where helically wound optical fibers are provided in a tube, to avoid mechanical stress in the fibers. Axial lengthening of the tube results in deformation (extension) of the helix.